Offline High Power Factor Triac Dimmable LED Driver GreenPoint® Reference Design

This reference document describes a built-and-tested,GreenPoint solution for a 13 W nominal constant current power factor corrected offline LED driver. This is intended for solid state lighting (SSL) applications such as commercial and residential LED downlights and spotlights that require high efficiency, power factor correction and triac dimming control. The power supply design is built around ON Semiconductor’s NCL30000 critical conduction mode fixed on-time flyback controller. The secondary side regulates a 350 mA constant current capable of driving a string of 1 W phosphor converted “white” LEDs. This reference design is optimized for driving 12 LEDs at 350 mA but the design is adaptable to accommodate a range of 4 to 15 LEDs in series with minor component modifications. The maximum power capability of this specific design is 15 W. The design is flexible and robust with output open and short circuit protection as well as optional thermal shutdown in the event that the operating temperature is exceeded.